How wide is too wide for tires ??

[Chad Stubblefield]

How wide can one go before it starts to get sloppy or squirmy?
Street tires. Dunlop's

I could use more grip in the rear.

wheels and tires currently are:
Front --- 18x8 245/40/18 should I go 255/35/18 ?
Rear ---- 18x9 265/35/18 should I go 275/35/18 ?

I know these wider tires will fit with minor rubbing in the front only.

camber maxed out in front:
front -1.5 degrees
rear -1.8 degrees but I could get a lot more

Im figuring for R's (Hoosiers) because of a stiffer side wall that going wider would be beneficial. But let me know if Im wrong.

thanks for the help

[Q V]

I can't give you direct answers about the dunlops, but when I went from 235 -> 255 & 265 on my 18x9 fronts, it felt MUCH sloppier for an event or two. I was faster though . The difference between the 255 & 265 was negligible - only thing I really noticed was fender rubbing w/ the 265's for my car.

265/35 -> 275/35 is probably going to hurt you just as much as help you:
- slightly bigger diameter tire ~.27" higher
- 4 more lbs per tire for the Dunlops going from 265 -> 275

That will probably be more noticeable than the slop (if any).

[Steve Ekstrand]

I run 265-35-18 Dunlops on an 18x8.5 rim and I don't notice any sidewall slop there. I'm sure a 275 on a 9" would be fine.

[John Coffey]

In BS it was common for the 350Z guys to run 285/30-18s on the stock 8" wide wheels. For that particular car it worked. The RX8 in BS worked better on 245s. As you can see there's not set rule and you'll have to test on your own car to see which gives you the best times. FYI... Rely on the stopwatch and ignore how the car "feels."